The Limits to Growth – 40 Years Out

The 1972 book,”The Limits to Growth,” publicized the results a group of MIT researchers reached after a three-year study on worldwide consumption levels and impacts. The MIT team warned that earth systems might collapse in the 21st century because total human consumption was exceeding earth’s carrying capacity. They backed their warning up with the best science and computer models available to them, and their book has sold 10 million copies since in 30 languages. I knew enough science to be convinced that there was a serious longterm environmental problem, and so were many other readers.

On March 16, 2012, Smithsonian.com published Megan Gambino’s interview with Dennis Meadows, who headed the MIT team which produced “The Limits to Growth.” Their exchanges give Meadows’s take on what’s happened in the 40 years since the study. I recommend that you read the interview in full, and a brief excerpt is provided below, while the entire article can be found here.

From 1970 to 1972, you and 15 others worked feverishly on The Limits to Growth. What were your goals at the outset of the project?
Jay Forrester, a senior professor at MIT, had created a theoretical model that showed the interrelationship of some key global growth factors: population, resources, persistent pollution, food production and industrial activity. Our goal was to gather empirical data to test his model and elaborate on it. We wanted to understand the causes and consequences of physical growth on the planet over a 200-year time period, from 1900 up to 2100.

According to the “standard run” or “business-as-usual” scenario, you predicted that we would overshoot the planet’s carrying capacity and collapse by mid-21st century. What do you mean by collapse?
In the world model, if you don’t make big changes soon—back in the ’70s or ’80s—then in the period from 2020 to 2050, population, industry, food and the other variables reach their peaks and then start to fall. That’s what we call collapse.

Now, in real life, what would that mean? It is not clear. In a way, it is like being in San Francisco and knowing that there is going to be an earthquake and that it is going to cause buildings to fall down. Which buildings are going to fall down, and where are they going to fall? We just don’t have any way of understanding that. What we know is that energy, food and material consumption will certainly fall, and that is likely to be occasioned by all sorts of social problems that we really didn’t model in our analysis. If the physical parameters of the planet are declining, there is virtually no chance that freedom, democracy and a lot of the immaterial things we value will be going up.

Of the experts talking about growth today and making forecasts for the future, who do you think really deserves attention?
I have always found Lester Brown [environmental analyst and author of World on the Edge] to be a source of very useful insights into what is happening mainly with food systems. He points out that in most areas of the world now we are over-pumping groundwater. Some of those groundwater aquifers aren’t recharged at all; they are what we call fossil water, and others have a rather low recharge rate. So, we are coming soon to the time where our use of those aquifers will not be able to exceed their annual recharge. That will mean that food that is currently being produced by overuse of water will need either to disappear or to come from very different methods. He makes that point forcefully.